Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the first image of a display screen or portion thereof with transitional graphical user interface showing my new design;

FIG. 2 is the second image thereof;

FIG. 3 is the third image thereof; and,

FIG. 4 is an enlarged view of the claimed portion of the GUI in FIG. 1, shown separately for completeness of illustration.

The outer broken lines in FIGS. 1 to 3 showing the mobile phone are included for the purpose of illustrating environmental structure and form no part of the claimed design. The broken lines showing the rectangular display screen or portion thereof form no part of the claimed design. The remainder of the broken lines illustrate portions of the graphical user interface and form no part of the claimed design.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1-3. The process or period in which one image transitions to another forms no part of the claimed design. 

CLAIM I claim the ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 